LIDAR (Light Detection And Ranging) systems have emerged as key components to Autonomous Driving systems. The systems are analogous to RADAR systems where visible or infrared light is used rather than radio waves. The device seeking the range finding information sends out a pulse (or stream of pulses) of light and measures the time for the pulse to hit an object and return. The distance to the object is then computed from the time-of-flight. Many of these systems have been tested in isolation and can be shown to work well.
In practice, these systems will not be operating in isolation. One common specification in the automotive application is to detect the distance to objects up to 200 yards away. If all of the vehicles in that range are using LIDAR, there can be thousands of light sources sending out light pulses and looking for returns. Hence, the receiver on any LIDAR system can receive a large number of light pulses that did not originate with that receiver. The receiver must then determine which pulses are returns from that receiver's transmitter and which are “noise”. Making this distinction presents a number of challenges.